src: refactor vcbuild configure args creation

remove a bunch of variables and rely on %config_flags% alone where
possible, also allow for an external %CONFIG_FLAGS% variable to supply
additional arguments to configure to match the behaviour of the Makefile

vcbuild.bat

@@ -15,8 +15,6 @@ if /i "%1"=="/?" goto help
 set config=Release
 set target=Build
 set target_arch=x86
-set debug_arg=
-set snapshot_arg=
 set noprojgen=
 set nobuild=
 set nosign=
@@ -28,15 +26,13 @@ set licensertf=
 set jslint=
 set buildnodeweak=
 set noetw=
-set noetw_arg=
 set noetw_msi_arg=
 set noperfctr=
-set noperfctr_arg=
 set noperfctr_msi_arg=
 set i18n_arg=
-set download_arg=
 set release_urls_arg=
 set build_release=
+set config_flags=
 
 :next-arg
 if "%1"=="" goto args-done
@@ -62,14 +58,13 @@ if /i "%1"=="test-internet" set test_args=%test_args% internet&goto arg-ok
 if /i "%1"=="test-pummel"   set test_args=%test_args% pummel&goto arg-ok
 if /i "%1"=="test-all"      set test_args=%test_args% sequential parallel message gc internet pummel&set buildnodeweak=1&set jslint=1&goto arg-ok
 if /i "%1"=="jslint"        set jslint=1&goto arg-ok
-@rem Include small-icu support with MSI installer
-if /i "%1"=="msi"           set msi=1&set licensertf=1&set download_arg="--download=all"&set i18n_arg=small-icu&goto arg-ok
+if /i "%1"=="msi"           set msi=1&set licensertf=1&set config_flags=%config_flags% --download=all&set i18n_arg=small-icu&goto arg-ok
 if /i "%1"=="build-release" set build_release=1&goto arg-ok
 if /i "%1"=="upload"        set upload=1&goto arg-ok
 if /i "%1"=="small-icu"     set i18n_arg=%1&goto arg-ok
 if /i "%1"=="full-icu"      set i18n_arg=%1&goto arg-ok
 if /i "%1"=="intl-none"     set i18n_arg=%1&goto arg-ok
-if /i "%1"=="download-all"  set download_arg="--download=all"&goto arg-ok
+if /i "%1"=="download-all"  set config_flags=%config_flags% --download=all&goto arg-ok
 if /i "%1"=="ignore-flaky"  set test_args=%test_args% --flaky-tests=dontcare&goto arg-ok
 
 echo Warning: ignoring invalid command line option `%1`.
@@ -85,19 +80,21 @@ if defined build_release (
   set config=Release
   set msi=1
   set licensertf=1
-  set download_arg="--download=all"
+  set config_flags=%config_flags% --download=all
   set i18n_arg=small-icu
 )
 
-if "%config%"=="Debug" set debug_arg=--debug
-if defined nosnapshot set snapshot_arg=--without-snapshot
-if defined noetw set noetw_arg=--without-etw& set noetw_msi_arg=/p:NoETW=1
-if defined noperfctr set noperfctr_arg=--without-perfctr& set noperfctr_msi_arg=/p:NoPerfCtr=1
+if "%config%"=="Debug" set config_flags=%config_flags% --debug
+if defined nosnapshot set config_flags=%config_flags% --without-snapshot
+if defined noetw set config_flags=%config_flags% --without-etw& set noetw_msi_arg=/p:NoETW=1
+if defined noperfctr set config_flags=%config_flags% --without-perfctr& set noperfctr_msi_arg=/p:NoPerfCtr=1
 if defined RELEASE_URLBASE set release_urlbase_arg=--release-urlbase=%RELEASE_URLBASE%
 
-if "%i18n_arg%"=="full-icu" set i18n_arg=--with-intl=full-icu
-if "%i18n_arg%"=="small-icu" set i18n_arg=--with-intl=small-icu
-if "%i18n_arg%"=="intl-none" set i18n_arg=--with-intl=none
+if "%i18n_arg%"=="full-icu" set config_flags=%config_flags% --with-intl=full-icu
+if "%i18n_arg%"=="small-icu" set config_flags=%config_flags% --with-intl=small-icu
+if "%i18n_arg%"=="intl-none" set config_flags=%config_flags% --with-intl=none
+
+if defined CONFIG_FLAGS set config_flags=%config_flags% %CONFIG_FLAGS%
 
 if not exist "%~dp0deps\icu" goto no-depsicu
 if "%target%"=="Clean" echo deleting %~dp0deps\icu
@@ -168,7 +165,8 @@ goto run
 if defined noprojgen goto msbuild
 
 @rem Generate the VS project.
-python configure %download_arg% %i18n_arg% %debug_arg% %snapshot_arg% %noetw_arg% %noperfctr_arg% --dest-cpu=%target_arch% --tag=%TAG%
+echo configure %config_flags% --dest-cpu=%target_arch% --tag=%TAG%
+python configure %config_flags% --dest-cpu=%target_arch% --tag=%TAG%
 if errorlevel 1 goto create-msvs-files-failed
 if not exist node.sln goto create-msvs-files-failed
 echo Project files generated.